The proposed work includes a broad range of projects in dental-oral physiology and biophysics. The major areas are as follows: 1. Investigation of the tooth pulp circulation, including pharmacological and metabolic control of the pulp capillary bed, the physiological role of pulp pressure in tooth eruption, spread of inflammation in the pulp, measurement of pulp blood flow rate by microcinematography and radioisotope washout, direct measurement of capillary pressure with the ultramicropressure transducer, and the relation of mechanical forces to the pulp circulation. 2. Physical properties of the tooth, including its electrical conductivity, diffusion coefficients, and thermal conduction. 3. Investigation of the periapical circulation in normal and pathophysiological states. 4. Neurophysiology of the tooth and its sensory representation in the central nervous system. 5. Behavioral and psychophysiological experiments quantitating pain of dental origin, and the factors which determine such pain. 6. Chemical sensation, including the response of chemoreceptive endings, and the neurophysiological basis of taste. 7. Clinical aspects of basic dental physiology, including the measurement of pulp pressure in endodontic emergencies, the role of pressure in influencing pulp blood supply and tooth eruption in humans, and the development of an experimental technique for evaluation of local dental anesthetics.